How hard is the short side? Take this morning. Right from the get-go, all of these silly Linux-related companies take off because of the Justice Department's plan to break up Microsoft. They are all up three and four points. Of course, these companies have very little in the way of fundamentals. They seem to go up solely as a function of whether Joel Klein growls or not.

So we figure, what the heck, let's sell some of the Linux-related stocks short . But before we can do that, we have to get a "locate" -- meaning we have to identify where we can get some shares to deliver as part of the short-selling mechanism. If we can't borrow the shares, when we sell them we won't be able to deliver them. (Even if you sell short, you still have to deliver those shares to the buyer. You have to borrow them.)

We look -- and there are no shares that can be borrowed. They are all let out ahead of us. So we can't short the stocks. We can't find them to borrow to send!

So the trade doesn't get done. You can't short what you can't borrow. Period.